For convenience' sake I group under this one head certain operations used for the relief of distortion, in which muscles or tendons are divided subcutaneously. Since the discovery of the principle by Delpech, and the application of it by Stromeyer, Dieffenbach, Little, and countless successors, it has been used for very many cases for which it is totally inapplicable, e.g. for the division of the muscles of the back in spinal curvature. Still there remain several deformities for the relief of which subcutaneous tenotomy is a most important remedy; chief among these are Wry Neck and Club-foot.

Operation for Wry Neck.—Subcutaneous section of the sterno-mastoid.—In what cases of wry neck is this operation suitable? In those only in which the muscles are the starting-point of the mischief. These are sometimes congenital, more frequently they commence in childhood. In cases where the distortion depends on disease of the cervical vertebrÆ, or is secondary to curvature of the spine, division of the muscle is worse than useless.

Operation.—A tenotomy knife, which should be sharp-pointed, narrow in the blade, with a blunt back, should be introduced through the skin a little to one side of the sternal portion of the affected muscle, passed along with its flat edge between the skin and the tendon, till it has fairly crossed the tendon; the blade should then be turned so that by a gradual sawing motion the edge may be made to divide the tendon about an inch above the sternum. A distinct snap will then be felt or heard, and the position of the head will be at once much improved. Exercise, warm bathing, and rubbing, will generally suffice to complete the cure, without it being necessary to call in the aid of the instrument-maker with his expensive apparatus.[166]

Operations for Club-Foot.—The following are the tendons which may require division in the cure of club-foot, and the operations for their division.

1. The tendo Achillis.—There are very few cases of true club-foot which can be successfully treated without division of the tendo Achillis. While in talipes equinis it is generally the only disturbing agent, in talipes varus and valgus it invariably increases and maintains the deformity, which the tibiales or peronei seem to originate.

Operation.—The foot being held at about a right angle with the leg, the operator should pinch up the skin over the tendon, introduce the knife flatwise, a little to one side of the tendon, till its point is nearly projecting at the other, then turn the edge on the tendon and cut inwards with a sawing motion till the tendon gives way with a distinct snap, and the foot can be completely flexed with ease.

2. Tibialis posticus.—Next in frequency and importance to that of the tendo Achillis, division of this tendon is much more difficult to perform. It may be performed either above or below the ankle.

(a.) Above the ankle.—The blade of a tenotomy knife should be entered perpendicularly at the posterior margin of the tibia, half an inch or an inch above the internal malleolus, so as to pass between the bone and the tendon of the tibialis posticus, the blade directed towards the latter; the assistant should now evert the foot, the operator pressing the blade against the tendon.[169]

(b.) Below the ankle, close to the attachment to the scaphoid. This is the better position of the two when the position of the tendon can be made out, which is not always the case, especially in cases of old standing.

Raising the skin just over the astragalo-scaphoid joint, the knife should be entered with its blade downwards, and across the tendon, and should be made to cut on the bone, while an assistant everts the foot till the tendon gives way with a distinct snap.

3. Tibialis anticus may in like manner be divided either just above the ankle, or at its insertion. When it requires division it can generally be made so prominent as to render its division comparatively easy.

4. Peronei.—These do not often require division, cases of talipes valgus being usually paralytic in character. If necessary they can be cut as they cross the fibula.

5. The plantar fascia, may require division; when this is the case, it is so prominent as to render the operation very easy, if conducted on the principles mentioned above.